test against incoming http-2 changes

  def handle_connection(conn, sock)

    super

    conn.on(:frame_received) do |frame|

      if frame[:type] == :ping && !frame[:flags].anybits?(HTTP2::ACK)

      if ping_frame?(frame)

        # received ping from client

        sleep @ping_delay

      end

    end

  end

  if HTTP2::VERSION >= "1.3.0"

    def ping_frame?(frame)

      frame[:type] == :ping && !frame[:flags].anybits?(HTTP2::ACK)

    end

  else

    def ping_frame?(frame)

      frame[:type] == :ping && !frame[:flags].include?(:ack)

    end

  end

end